Thanks for the info Mal
My wire is flexweave, the un-insulated type. Last week I was impressed by the frost on the wire it made it look really fat. I did not actually measure the amount of frost but eyeballed it at 10mm. But I could not detect any change to the loading (I use fixed tapped coil with coupling loop), busness as usual you miight say. I am sure there must be some effect but I could not see with my gear.
This flexweave has let me down because early last year it broke. The thin wires that make it up seemed very corroded and brittle so I am expecting the repaired wire to come down again. I am thinking of replacing it using 1.5mm or thereabouts diameter hard drawn copper for durability, what do you think?
I have basically 4 radials of various diameter in H fashion running the property boundry with the up lead at about 1/3 offset to centre of the H, best I can do at the moment. The ant is inv "L" 40m lng up abt 13m.
If it wasn't for the 11kV at the bottom of the garden I could do a lot better.... hee. 73 es GL petefmt --- On Tue, 12/1/10, mal hamilton <[email protected]> wrote:
From: mal hamilton <[email protected]>
Subject: Re: LF:Ice and frost on 600m antenna
To: [email protected]
Date: Tuesday, 12 January, 2010, 14:25
Pete
I use 1.5mm insulated multi strand wire normally but sometimes 2.5mm but since it is insulated the WX seems to have little effect on it.This is the 1/4 wave inv L TX antenna.Other antennas here use the same type of wire and again the WX has little effect.
My radials are also insulated 2.5 mm.
Bare copper wire might be more vunerable to WX changes.
de mal/g3kev
----- Original Message -----
Sent: Tuesday, January 12, 2010 1:51 PM
Subject: LF:Ice and frost on 600m antenna
Hi LF Group
In an attempt to calculating the effect of ICE (Haw frost) on my antenna I get these results.
With a wire diameter of 1.5mm flex weave, it comes out to 1.1 amps for 60 watts RF applied. This is confirmed crudely by observing a pair of car festoon lamps (12Vx0.5A each) in parallel in the antenna up lead glowing to full brightness.
With an estimated increase in antenna wire diameter to 10mm caused by the Haw frost I did not notice any change in antenna current by this method.
Running the calculation through using a 10mm wire I get 1.2 amps and again to an absurd size of 20mm diameter there is virtually no increase in current.
The recent WX at this location has had no noticeable effect on the antenna. If it did I would suspect leakage through a dodgy insulator at the top of the inverted “L” up lead.
The type I use is a deeply ribbed glass insulator about 8 inches long.
73 es GL petefmt
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